RDFS provides primitives for defining lightweight schemas for RDF triples. It allows defining classes of resources and relations between resources, and organizing their hierarchies. RDFS defines domains and ranges for relations, and provides semantics and inference rules for reasoning about subclasses, subproperties, and types of resources.

1. in a nutshell RDFS fabien, gandon, inria

2. R D F is a triple model i.e. every piece of knowledge is broken down into ( subject , predicate , object )

3. RDF S stands for R D F Schema

4. RDF S provides primitives to write lightweight schemas for R D F triples

5. long way a little drop of semantics goes a

6. RDF S provides primitives to... ... define the vocabulary used in triples ... define elementary inferences

7. RDF S to define classes of resources and organize their hierarchy

8. DOCUMENT REPORT

9. RDF S to define relations between resources and organize their hierarchy Tom Doc13 AUTHOR

10. CREATOR AUTHOR

11. RDF S allows for multiple inheritance for classes and properties

12. PERSON MAN MALE

13. RDFS relations have a signature DOMAIN RANGE

14. RDFS relations have a signature ... the domain is the type of the resource the relation starts from. ... the range is the type of the resource the relation ends to.

15. RDFS relations with several... ... domains mean all domains apply. ... ranges mean all ranges apply. Ranges and domains are optional

16. but looks like object programming,

17. properties are first class citizens, they are not defined inside classes, they have their own hierarchy.

18. no overwriting in particular a property can not be refined for sub classes of its range or domain.

19. multi-instantiation a resource can have several types, it can be the instance of several classes like multiple lights, facets on a resource.

20. RDF S provides primitives to... ... give labels ... ... give comments ... ... for classes and properties

21. RDF... RDFS using the XML syntax for

22. <rdf:RDF xml:base=&quot;http://inria.fr/2005/humans.rdfs&quot; xmlns:rdf =&quot;http://www.w3.org/1999/02/22-rdf-syntax-ns#&quot; xmlns:rdfs=&quot;http://www.w3.org/2000/01/rdf-schema#&quot; xmlns=&quot;http://www.w3.org/2000/01/rdf-schema#> < Class rdf:ID=&quot; Man &quot;> < subClassOf rdf:resource=&quot;# Person &quot;/> < subClassOf rdf:resource=&quot;# Male &quot;/> <label xml:lang=&quot;en&quot;>man</label> <comment xml:lang=&quot;en&quot;>a male person</comment> </Class>

23. <rdf: Property rdf:ID=&quot; hasMother &quot;> < subPropertyOf rdf:resource=&quot;# hasParent &quot;/> < range rdf:resource=&quot;# Female &quot;/> < domain rdf:resource=&quot;# Human &quot;/> <label xml:lang=&quot;en&quot;>has for mother</label> <comment xml:lang=&quot;en&quot;>a female parent</comment> </rdf:Property> </rdf:RDF>

24. RDF S semantics : standard inference rules to derive additional triples from known statements.

25. example of type propagation IF (c 2 , subClassOf , c 1 ) AND (x, type , c 2 ) THEN (x, type , c 1 ) IF (Man, subClassOf , Person) AND (Tom, type , Man) THEN (Tom, type , Person)

26. example of property propagation IF (p 2 , subPropertyOf , p 1 ) AND (x, p 2 , y) THEN (x, p 1 , y) IF (author, subPropertyOf , creator) AND (Tom, author, Report12) THEN (Tom, creator, Report12)

27. example of subClass transitivity IF (c 2 , subClassOf , c 1 ) AND (c 3 , subClassOf , c 2 ) THEN (c 3 , subClassOf , c 1 ) IF (Person, subClassOf , Animal) AND (Man, subClassOf , Person) THEN (Man, subClassOf , Animal)

28. example of subProp transitivity IF (p 2 , subPropertyOf , p 1 ) AND (p 3 , subPropertyOf , p 2 ) THEN (p 3 , subPropertyOf , p 1 ) IF (parent, subPropertyOf , ancestor) AND (father, subPropertyOf , parent) THEN (father, subPropertyOf , ancestor)

29. example of domain inference IF (p 1 , domain , c 1 ) AND (x, p 1 , y) THEN (x, type , c 1 ) IF (author, domain , Human) AND (Tom, author, Report12) THEN (Tom, type , Human)

30. example of range inference IF (p 1 , range , c 1 ) AND (x, p 1 , y) THEN (y, type , c 1 ) IF (author, range , Document) AND (Tom, author, Report12) THEN (Report, type , Document)

31. summary take-home message on RDF S

32. RDF Schema to... ... define classes and relations of resources and organize their hierarchy ... define signatures of relations (domain, range) ... document them with labels and comments ... define associated inference rules

33. fabien, gandon